Electric-elevator brake.



C. W. WHEELER. ELECTRIC ELEVATOR BRAKE. APPLICATION men 0cm I Patented Apr. 4, 1916.

C /arnce W Whe/er by his dt'toi-ney,

T0 OTIS. ELEVATOR COMPANY, NEW JERSEY.

Specification of Letters Patent.

rrn s'r 'rns PATENT orrrcn.

CLARENCE W. WHEELER, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS,

0F JERSEY CITY, NEW JERSEY, A CORPORATION OF ELECTRIC-ELEVATOR BRAKE.

Application filed October 1, 1906. Serial No. 336,901.

fl '0 all whom it may concern:

Be it known that I, CLARENCE W. l/Vn unnnn, a citizen of the United States, and a resident of Chicago, in the county of. Cook and State of Illinois, have invented a certain new, useful, and Improved Electric-lllevator Brake, of which the following is a full, clear, and exact description, suchas will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to electric elevators, and particularly to automatic brakes for electric elevators.

,Through inadvertence of the operator or faulty working of the mechanism it sometimes occurs that an elevator car is carried beyond its proper stopping point at the top or bettom of the shaft, with consequent damage to the building, or to the hoisting mechanism and not infrequently inflicting serious injury upon the occupants of the car.

The object of my invention is to provide improved emergency brake operating mechanism.

More particularly it is the object of my invention to provide automatic means for effecting the application of a brake at predetermined limits of travel of elevator hoisting mechanism and combining therewith an auxiliary device to operate emergency brakeapplying mechanism beyond such h mits and having, a single eleetro-magnet which will be capable of releasing the brake both at the limits of travel and beyond such limits. Y

A further object of my invention is the provision of means for effecting the application of abrake at the limits of travel of a hoisting machine and combining therewith stop-motion apparatus which will exert an extra squeeze on the brake beyond such limits, and ,having a single electro-magnet capable of releasing th brake after such extra squeeze has been exerted as well as at the ordinary limits of travel.

Other objects of the invention will appear hereinafter, the novel features and combinations of elements being set forth in the appended claims.

My invention will be more readily understood by reference to the accompanying drawing which form a part of this spec fif "by an electric motor,

magnetic release.

cation, and in which the figure is' a side elevation of an electric elevator hoist equipped with a brake constructed in accordance with my invention.

cludes a cable drum which I prefer to drive a brake, a brake-applying mechanism, and a separate mechanism for automatically breaking the motor circuit when the car arrives at a predetermined point.

The cable winding drum, 3, (the cable being omitted) is mounted on ashaft driven by a worm gear (not shown) inclosed by a frame or housing. 4, the lower portion of which contains oil in which the worm rotates. ()n the shaft, 5. preferably between the motor and the gear housing, is fixed a brakewheel, 7, which, when checked bythe brake, stops the motor shaft, the drum, 3, and the elevator. The brake is constructed for mechanical actuation and preferably electro- To that end it preferably comprises a pair of brake-levers, 8, provided with large friction surfaces to engage opposite sides of the face of the brake-Wheel. The friction surfaces may be metallic or nonmetallic; as shown, the shoes are lined with strips, 9, of wood or other material which offers a high degree of friction with the pressure of the springs at desired-times.

The simplementary action is brought about by auxiliary brake operating mechanism so constructed and arranged as tobe operated by the last part of the movement of the hoisting mechanism in either direction, 11. 6., at moments when the elevator car approaches the top or the bottom of the ele vator shaft,

Patented Apr. 4, 1916.

The mechanism shown in the drawings inas I provided with an The means for applying the brake-levers to the bralccwhcelpreferably comprise a roclniblo member, means for rocking it, and pull-rods actuated thereby and connected to the braluz lercrs through the medium of springs. As shown, a disk, 15, on a rockshaft, 16, artuates two rods 17, which pass through slots in the brake-levers, 8, but are not pivoted to the latter. The springs, 18, are interpusru'l between the levers, 8, and nuts, ll), on the rods, 17, for the purpose hcreinbefore stated. The rockshaft, 16, is

which is a rod, actuated by a cam-operated lever, if the rod, rises to apply the brake, the cam, 24., is arranged above the lever, 23, shown. The cam is loosely mounted on a screw shaft, 25, and is actuated as hereinafter described. It is eccentrioally fOlIl'llZ-lti, and its lowest portion is held, normally above the cam lever roller, thereby leaving the parts in the positions shown. Even in this position of the parts, the springs, 18, exert braking pressureupon thebrake-love, 8, this pressure being emplayed for s ping the elevator at the intermediate ilor: 5. y

an additional safeguard I provide an auxiliary or supplementary brake-applying morals for Giltrltlt'lj an extra squeeze on the brake when the elevator winding mechanism spring 26 may he travels beyomfl its ordinary limits by reason of momentum or otherwise.

if desired, tie springs 18 may be depended upon for tl dinary braking operation between limit ing on its we brake shoe. In such may be omitted. It will nulira-applying springs 18, to t id to draw the brakelust the surface of the even when all the are used their combined uncut to prevent the brakemagnet from alarming the brake beyond the ordinary limits of travel after the emergency braheapplyiu meanshas operated. In some case, it of advantage to employ the spring 2t in addition to the springs 18, 18 because the safety of the brake apparatus is iucrrmsed. If one of the springs 18 should break, the spring 20 may be relied upon to apply the brake-shoe associated with such and the springs 18, 1.8 relied upon for the ordinary application of the brake and one of the springs .18 should become broken, suilicient force could be transmitted through this other spring 18 by the emergency brake-applying means to apply shoe to the pulley to eii'cctually stop the elevator winding mechanism before the latter traveled too far beyond its ordirary limits. It should be understood that although the used for applying life arm, 20, connected to,

: 'avcl, each spring 18 actshort at least one brakebetween the limits of travel of the elevator" winding mechanism. At the ordinary limit of travel of the winding mechanism one of the stop-motion devices comes into play to cut off the current from the bruise-magnet; therefore the springs will apply the brake in the usual manner. If this is insuliicient, however, to stop the elevator winding mechanism by reason of too much momcn' tum or otherwise, the supplementary or auxiliary stop-motion device will afterward come into play to operate the emergency brake-applying means and transmit additional force through the cam 24, the lever 23, the rod 22, the arm 20, disk 15, links 17, 17 and springs 18, 18, thereby exerting an extra squeeze on the brake-shbes After the elevator Winding mechanism has been stopped by the emergency brakenpplying means, the springs 18, 18 may be further compressed by the energization of the brake magnet so that the brake can be released and. the elevator started in the opposite direction.

It should be particularly noted that since the same brake-magnet which is used beratus, the operator is notrequired to reset the apparatus by manual manipulation at the winding mechanism but may release the brake by an electric switch at a distance.

It should be understood that the right hand end of the spring 26 acts on the disk 27, which is attached to the rod 28, shown at the left, and that the spring 26 also acts on the left hand disk 27, which is attached to one or two rods shown at the right. Preferably this construction consists of two rods 28 at one side passing loosely through the disk on the same side and a single rod upon the other side passin loosely through the disk at the correspon ing side. The spring 26 therefore acts on both brake shoes 8, 8 to urge the same toward the brake pulley in a manner well understood.

The means for retracting the brake and holding it ofi during travel of the elevator car, are preferably electromagnetic. An em bodiment of this idea consists of a solenoid, 10, provided with two iron cores or plungers, which are loosely connected to the ends of the brake-levers, 8,- said cores being drawn apart when the brake-levers are set. Said levers are pivoted on lugs, 14, which may be integral with the iron shell, 13', inclosing and supporting the solenoid. Said shell is held by the gear housing, 4. When the magnet, 10,

in its cores, which turn the brake-levers and is energized it pulls the cable drum, 3, is provided with an eX-' augmenting the normal braking pressure,

automatically, is driven by the elevator drive mechanism, as more fully described 'liereinafter. The auton'iatic mechanism for throwing the limit switch is also driven by the elevator drive mechanism and is pre'i' erablyconstructed as follows: The shaft of tension, 29, the outer portion of which is screw threaded and the: inner portion smooth. Fixed upon the inner portion c., adjacent to the housing, 4,is a gear or pinion, 30, and loosely mounted at one side of said gear, is a gear or pinion, 31, which is secured to or integral with a grooved wheel, 32, and is also secured to a double yoke, 33, which also turns freely upon the extension, or screw shaft, 29. The yoke and gear, 31, are held normally in a. certain position, by means of a weight, attached to a flexible member one end of which is attached to the periphery of said grooved wheel, 32.

The loose gear or pinion, 31, meshes with a driven gear, 40, on a rotary shaft, 41, journaled in a rigidly supported housing, 42. Upon shaft, ll, isarranged a rotary limit switch, comprising preferably, a suitable number of contact segments .or rings, contact fingers or brushes arranged to make and break contact andgipen or close circuits when the rings or segnibnts are turned. This limit switch, designated LS'as its name-implies, is operated only at or near the limits of the cars travel, and its office is to slow the motor, when the car approaches the top or bottom of its shaft, and then to break the motorcircuit, before the car arrives at the top or bottom landing.

The rotary portion of. the switch is held yieldably in normal position by the gears, 31 and 4.0 and the weight connected to the gear 31 and yoke 33. 'In this position the contact lug, 46, is in contact with two of the fingers, 47. The contact fingers are held In any suitable manner, for example as shown in Figs. 3 and 4, their holders being insulated from the metal rod, 49. The other contact fingers are normally upon the middle pointsot' the segments, 44-45, and the operation of the switch is the same, in bothdirections,ofniovement, e. when the car moves either up.or down.-

The contact lingers,-47,'of the limit switch are connected in circuits of several relay or magnet operated switches, all on a controller board (not shown). termed respectively, a line switch, an operating switch, and a motorslowing switch. All said switches are held closed when the limit switch is at normal, or centered. The

with

.51, to follow the screw shaft,-25, is mminted a yoke,

' ing integral Said switches may be resistance is cut out, reducing the speed of the motor; the armature circuit is then broken, and finally the solenoid, 10, is deenergized, permitting the brake to be applied.

circuit of the retracting prior to the supplementary application the brake by the auxiliary mechanism.

The means by which the limit switch is operated may be, and are shown as, carried by the screw shaft, 29, within the yoke, 33. Two dogs, 50, are tightly clamped upon the screw, 29,, their distance apart being deter mined. by the length of the elevator shaft. Each is provided with tooth, 50'. Between them, is atraveling nut N, having two teeth, 51, and having extensions, 51 that engage ribs, 33', in the frame, 33, while permitting the nut to travel upon the screw shaft, 29, when the yoke is not being rotated. The dogs, 50, are so spaced that one or the other will engage a tooth, 51', of the nut, N, when the elevator car comes within a predetermined distance from the end of its travel, As soon as this occurs, the nut will be. caught and turned at the same speed as the screw, while its longitudinal motion will bearrested. By turning, itwill turn the yoke, 33, wheel, 32, gears, 31 and 40, and the limit switch. The said movement of the wheel, 32, willdraw up the chain and weight connected thereto. Upon the reverse movement of the car, (either up or down) the weight, acting through the chain, will cause the nut, dog, 50, back until the weight descended as far as it may. At this point the weight stops the rotation of the yoke, 33, hence the nut, 51, and the latter begins to move along the screw toward the opposite dog,':)(). 7 The mechanism. for automatically increasing the normal braking pressure near the.

magnet, isopened of The preferred construction is such that thelimits ofthe elevators travel, is shmivn'as a duplicate of that above described.

vided with a; chain'wheel, 54, chain, 55, and a weight, 56, for holding it centered. The screw shaft, 25, is provided with a gear, 57, which is turned by the gear, 30, fixed upon the upper screw-shaft, 2%). The cam, 24, be-

.with or secured to the chain wheel, 54, is held normally by the weight, 56, in the position shown. The dogs, 58, on screw shaft. .25, are so adjuste d that one of them will be engaged by, or engage, the nut, 59, when the elevator car is within'a short pre- -13) determined distance of its terminal stopping On the 53, pro

net, 10, when the operator starts the canon points, and after the limit switch has been operated. The positive rotation of the cam, 24, by the frame, 53, forcibly moves the lever, 23, and actuates the rod, 22, rock-arm,

. 5, 20, disk, 15, brake rods, 17, and the brake le vers, 8, the pressure being transmitted to said levers through the medium of springs,

' 18. It is evident that said springs will peroperator, the circuit through the solenoid,

springs,

just-meat, such switch, (not shown) 10, will be interrupted, thereby releasing the brake-levers to the springs,- 18, which will apply them with moderate pressure to the brake-wheels, 7. The pressure of the 18, may be varied by adjusting the nuts, 19;and the brake pressure at intermediate stops may also'be regulated without turning said nuts, if the connecting rod, 22, be provided with means forlongitudinal ad as a turn-buckle. As the brake shoes wear away the rod may be shortened accordingly lihe solenoid circuit includes, for each direction of the car, an operating magnet switch and a line magnet which are closedby the manuallyoperated controller on the car when the is released. part of an elevator controller which is not 5 carried upon the car.

Supposing'the car to be stopped at a point midway between the top and bottom floors, the operation is as follows: The operator starts the motor, which rotates the drum 3,

screw shaft, 29, and gear wheel, 30, thereon.

the brake arms away en r ze snar -e Gear, 30, turns the lower screw shaft gear wheel, 57. At a determined point, near the limit of travel of the car, the yoke, 33, on the upper screw shaft begins to revolve, and causes the pinion, 31, to turn the limit switch gear wheel, 40, which operates the limit switch, and the latter causes the speed of the motor to be reduced. Further movement breaks the motor circuit and then opens the 0 .brake magnet circuit.

When the magnet circuit is opened, the magnet, being deener ized, ceases to hold mm the brake Wheel, hence said arms are set against the wheel by the pressure of the springs 18 and 26. A further action follows immediately, that is, continued rotation of theshaft 25 causes the traveling nut 59 to engage'one or the other of the nuts 58, hence the yoke 53 is rotated and carries with it the cam wheel 24, thereh further setting the brakes by drawing up themed-22. a

The initial actio of the brake which occurs at the moment that the magnet is dewith the supplementary skilled in the art, elevator is started; thus the brake, Elaid magnet switches forms a braking action through the medium of the yoke cam, and rod'22 is suflicient to bring the car to a stop at the desired point at all times notwithstanding variation in speed of the car or its load.

The primary action of the brake is depended upon to bring the car-nearly to a stop when loaded heavily, or when moving at a high speed, and is also capable of bringing the car to a smooth even stop under light loads. I depend upon the action of the cam and the other members of the limit hralrc to apply the force which is necessary to stop the car, when the speed or Wei ht of the car is such that the primary actlon is insufficient. In other words the limit brake goes into action whenever the slip of the brake wheel for any reason becomes-excessive.

TVhen the operator manipulates the car controller to start the car, the solenoid, 10, is energized and retracts the brake; the weights, attached to the sheave 32 and the weight 56, descend and bring the limit switch and cam, 24, respectively, to normal. The motor may be run at full speed or at any desiredlower speed, at the will of the operator.

As various modifications of the invention will readily suggest themselves to one I do not limit my invention to the specific form and constructions herein described.

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

1. In a brake, the "combination with brake shoes, of means for applying the same, and automatic means acting through the brake applying means for increasing the application of the brake shoes. A

:2. In a brake, the combination with brake shoes, separate springs each applying a shoe with normal pressure, means for increasing the application of the shoes through the said springs, and a single electromagnet for releasing the said shoesboth when' applied with normal pressure and when under extra pressure.

In a brake, the combination with brake shoes, of a main spring for applying said shoes, auxiliary springs each applying one of-thc shoes, automatically operated means for exerting an extra squeeze on the shoes through the auxiliary springs and a single elcctromagn-et for'releasing said shoes both under normal pressure and after the extra squeeze has been exerted.

4. In a brake, the combination with a pair of brake shoes and means for applying the name, of a normally stationary lever mounted on a fixed fulcrum, pivoted at their innercnds to said lever, abutments one at the outer end of each of said rods, springs one interp sed between actuating rods i "6 shoes,

each abutment and a brake shoe, and means for moving said lever to efiect an extra squeeze on the brake shoes.

5. In a brake, the

to apply sure, a springs,

, the lever at its fulcrum,

10 mected between said springs lating member and lever fulcrumed ,lever to eii'ect extra squeeze on shoesgthroughsaid springs.

combination with oftwo separate springs each acting one of said shoes with normalpresbetween said an oscillating member connected to a pair of and said os'oilmeans for actnatingsaid s the brake links con- .6. In a brake, the, combination with brake brakeshoes, of means for applying the shoes,- automatic means acting through the brake-applying means for increasing the application, of the brake shoes, and an electromagnet for releasing said shoes after said additional force has been exerted.

In testimony whereof, I have hereunto set my hand, this 24th day of September, 1906,

in he presence of, two subscribing'witnesses.

.1 GL RENCEW. WHEELER.

1 CHARLES GIIBER'l IHAWLEY,

M,Smon. V 

